From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Letter to a piston ring supplier about an investigation into over-oiling and oil consumption linked to uneven bedding on scraper rings.
| Identifier | ExFiles\Box 148\3\ scan0394 | |
| Date | 23th September 1938 | |
| 1256. EXPERIMENTAL DEPARTMENT. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}5/JH. 23rd. September, 1938. Messrs. Wellworthy Piston Rings, Lymington, Hants. For the attention of Mr. Blackith. Dear Sirs, We are sending under separate cover for your inspection, one scraper ring, which has been removed from an engine, in connection with our investigation of oil consumption and control. You will notice the peculiar bedding on one land of the ring, adjacent to the slots. This uneven bedding was responsible for serious over-oiling at low speeds. The worst condition being at tick-over, where the higher depression caused the fault to be shown up at its worst. The remaining five scrapers showed the same effect, and it was noteworthy, that as the rings bedded in so the over-oiling decreased, they being inspected at intervals without removing them from the pistons. We would appreciate your considered opinion on the following points. (1) We have noticed that the rings we use can be put permanently out of shape by bending manually. As the rings have to be stretched over the pistons by hand when fitting, is it not possible that they can be thus distorted? (2) With reference to the sample scraper ring, could the same distortion account for the uneven bedding? remembering that this is adjacent to the slots, which are in turn the weakened portions of the rings. (3) Finally, we are trying a set of scraper rings, one land of each ring being reduced by .004 on the Cont'd.{John DeLooze - Company Secretary} | ||